Currently, most users visit a page in a manner that the user sends a request initiatively, and a server responds to the request passively, such that if the user wants to obtain a feedback of the server to obtain the information that he needs, he must send the request first. If the user wants to track a change of the information, a manual inspection shall be performed continuously, thus wasting a lot of time and effort. The user cannot be notified after the server is updated, such that the page content update cannot be realized by the user timely, thus resulting in a poor user experience. Moreover, since what are focused by the users are greatly different from each other, it is required to browse and compare the whole page each time, thus wasting a lot of sources and time and resulting in a low efficiency.